(a) Field of the Invention
The present invention relates to a semiconductor device having a module board and, more particularly, to a semiconductor device having a module board mounting thereon a plurality of electric components and mounted on a mother board.
(b) Description of the Related Art
In conventional personal computers or servers, memory devices such as DRAM devices are directly mounted on a mother board. However, memory module boards are increasingly employed recently, wherein a printed circuit board mounting thereon one or a plurality of memory devices is separately prepared, and then mounted on a mother board via a plug-socket coupling.
FIG. 9 shows a conventional semiconductor device having such a memory module board. The semiconductor device 200 includes a mother board 20 having a socket member 40 of a U-shaped cross section, and a memory module board 10 having a plug member and mounted on the mother board 20 by using the plug-socket coupling. The socket member 40 includes a plurality of contact terminals 41 arranged in two rows corresponding to pad terminals provided on both surfaces of the memory module board 10, whereby the memory module board 10 is detachably mounted on the mother board 20.
In the memory module board 10, the amount of heat generated in the memory devices 12 is more and more increasing along with a higher read/write operation and a higher density of memory cells in the memory devices 12. The increased amount of heat raises the operating temperature within the memory devices 12 and sometimes causes a degradation of the performance or thermal destruction of the memory cells. For preventing such degradation of the performance or destruction of the memory cells, it is essential to effectively diffuse the heat generated in the memory cells and suppress the temperature rise of the memory cells.
Patent Publications JP-10(1998)-335546A and -2004-079940A describe a technique wherein a heat radiation member is provided on the memory module board to diffuse the heat through the surface of the memory module board.
A higher read/write operation and an increased density of the memory cells in the up-to-date memory module boards hinder the effective suppression of temperature rise of the memory devices in the memory module boards, even in the case of the memory module boards described in the above publications. Thus, it is desired to effectively diffuse the heat generated in the memory cells, to assure the stable performance of the semiconductor devices including the memory cells.